World Bulletin / News Desk 

Russian hackers penetrated sensitive parts of the White House computer system after intruding at the U.S. State Department in recent months, CNN reported on Tuesday, citing U.S. officials briefed on the matter.

The White House said the report did not refer to a new incident but was "speculating" about the source of cyber activities that were disclosed last year.

Spokesman Mark Stroh said in a statement that the White House would not comment on CNN's attribution of the cyber attack to Russian hackers.

White House deputy national security adviser Ben Rhodes said in an appearance on CNN on Tuesday that the White House in 2014 disclosed cyber intrusions that did not affect classified information.

"We have an unclassified system and then we have a classified system, a top secret system," Rhodes said. "We do not believe that our classified systems were compromised."

CNN said the hackers gained access to unclassified but potentially sensitive information such as non-public details of the president's schedule.

White House: hacking event not new, no comment on who responsible

"This report is not referring to a new incident - it is speculating on the attribution of the activity of concern on the unclassified ... network that the White House disclosed last year," White House spokesman Mark Stroh said in a statement.

"Any such activity is something we take very seriously. In this case, as we made clear at the time, we took immediate measures to evaluate and mitigate the activity. As has been our position, we are not going to comment on the referenced article's attribution to specific actors."